package server

import (
	"context"
	"database/sql"
	"html/template"
	"log/slog"
	"sync"
	"time"

	"github.com/writekitapp/writekit/internal/build/templates"
	"github.com/writekitapp/writekit/internal/markdown"
	"github.com/writekitapp/writekit/internal/tenant"
)

type renderedPage struct {
	path string
	html []byte
	etag string
}

func (s *Server) rebuildSite(ctx context.Context, tenantID string, db *sql.DB, host string) {
	q := tenant.NewQueries(db)
	settings, err := q.GetSettings(ctx)
	if err != nil {
		slog.Error("rebuildSite: get settings", "error", err, "tenantID", tenantID)
		return
	}

	posts, err := q.ListPosts(ctx, false)
	if err != nil {
		slog.Error("rebuildSite: list posts", "error", err, "tenantID", tenantID)
		return
	}

	baseURL := getBaseURL(host)
	siteName := getSettingOr(settings, "site_name", "My Blog")
	siteDesc := getSettingOr(settings, "site_description", "")
	codeTheme := getSettingOr(settings, "code_theme", "github")
	fontKey := getSettingOr(settings, "font", "system")
	isDemo := getSettingOr(settings, "is_demo", "") == "true"

	pageData := templates.PageData{
		SiteName:   siteName,
		Year:       time.Now().Year(),
		FontURL:    templates.GetFontURL(fontKey),
		FontFamily: templates.GetFontFamily(fontKey),
		Settings:   settingsToMap(settings),
		NoIndex:    isDemo,
	}

	var pages []renderedPage
	var mu sync.Mutex
	var wg sync.WaitGroup

	addPage := func(path string, html []byte) {
		mu.Lock()
		pages = append(pages, renderedPage{path, html, computeETag(html)})
		mu.Unlock()
	}

	postSummaries := make([]templates.PostSummary, len(posts))
	for i, p := range posts {
		postSummaries[i] = templates.PostSummary{
			Slug:        p.Slug,
			Title:       p.Title,
			Description: p.Description,
			Date:        timeOrZero(p.PublishedAt),
		}
	}

	wg.Add(1)
	go func() {
		defer wg.Done()
		homePosts := postSummaries
		if len(homePosts) > 10 {
			homePosts = homePosts[:10]
		}
		data := templates.HomeData{
			PageData: pageData,
			Posts:    homePosts,
			HasMore:  len(postSummaries) > 10,
		}
		data.Title = siteName
		data.Description = siteDesc
		data.CanonicalURL = baseURL + "/"
		data.OGType = "website"

		html, err := templates.RenderHome(data)
		if err != nil {
			slog.Error("rebuildSite: render home", "error", err)
			return
		}
		addPage("/", html)
	}()

	wg.Add(1)
	go func() {
		defer wg.Done()
		data := templates.BlogData{
			PageData: pageData,
			Posts:    postSummaries,
		}
		data.Title = "Posts - " + siteName
		data.Description = "All posts"
		data.CanonicalURL = baseURL + "/posts"
		data.OGType = "website"

		html, err := templates.RenderBlog(data)
		if err != nil {
			slog.Error("rebuildSite: render blog", "error", err)
			return
		}
		addPage("/posts", html)
	}()

	for _, p := range posts {
		wg.Add(1)
		go func(post tenant.Post) {
			defer wg.Done()

			contentHTML := post.ContentHTML
			if contentHTML == "" && post.ContentMD != "" {
				contentHTML, _ = markdown.RenderWithTheme(post.ContentMD, codeTheme)
			}

			interactionConfig := q.GetInteractionConfig(ctx)
			structuredData := buildArticleSchema(&post, siteName, baseURL)

			data := templates.PostData{
				PageData: pageData,
				Post: templates.PostDetail{
					Slug:        post.Slug,
					Title:       post.Title,
					Description: post.Description,
					Date:        timeOrZero(post.PublishedAt),
					Tags:        post.Tags,
				},
				ContentHTML:       template.HTML(contentHTML),
				InteractionConfig: interactionConfig,
			}
			data.Title = post.Title + " - " + siteName
			data.Description = post.Description
			data.CanonicalURL = baseURL + "/posts/" + post.Slug
			data.OGType = "article"
			data.StructuredData = template.JS(structuredData)

			html, err := templates.RenderPost(data)
			if err != nil {
				slog.Error("rebuildSite: render post", "error", err, "slug", post.Slug)
				return
			}
			addPage("/posts/"+post.Slug, html)
		}(p)
	}

	wg.Wait()

	for _, p := range pages {
		if err := q.SetPage(ctx, p.path, p.html, p.etag); err != nil {
			slog.Error("rebuildSite: save page", "error", err, "path", p.path)
		}
	}

	slog.Info("rebuildSite: complete", "tenantID", tenantID, "pages", len(pages))
}